Technical Field
The invention relates to a sensing circuit. Particularly, the invention relates to a biomedical signal sensing circuit.
Related Art
Along with development of technology and progress of the times, people pay more and more attention to personal health, and various health-related industries are quickly developed. In order to accurately grasp various biomedical signals on human body, various manufactures have developed a wide range of instruments for measuring biomedical signals, for example, an electrocardiograph (ECG) machine, an electroencephalogram (EEG) machine, etc.
However, in a current biomedical signal sensing circuit, when a plurality of biomedical signals are simultaneously sensed, a plurality of independently operated sensing circuit has to be used for sensing. Since each of the sensing circuits has a little mismatch, outputs of the sensing circuits have to be summed and fed back to input terminals of the sensing circuits according to a common-mode feedback method, so as to increase a common-mode rejection ratio (CMRR). However, such method not only wastes a chip fabrication area, but also causes extra power consumption.